# Time zone meeting planner

Finds the time on a date when the same working hours overlap in up to 5 time zones, and shows it on each zone’s clock.

- Page: https://www.acalculator.org/days/time-zone-meeting-planner
- JSON spec: https://www.acalculator.org/days/time-zone-meeting-planner.json
- Version: d1f8b45690d0

## Default answer

Example with the default inputs (Your time zone New York (US Eastern), Time zone 2 London, UK, Time zone 3 Berlin, Germany, Time zone 4 None, Time zone 5 None, Date October 19, 2026, Working hours start 09:00, Working hours end 17:00) on the example date Monday, October 19, 2026: On October 19, 2026, working hours of 9:00 AM to 5:00 PM overlap for 2 hours in every chosen time zone.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| zone1 | Your time zone | The first time zone; the date is a date in this zone (IANA name). |
| zone2 | Time zone 2 | Another time zone to meet with (IANA name), or None. |
| zone3 | Time zone 3 | Another time zone to meet with (IANA name), or None. |
| zone4 | Time zone 4 | Another time zone to meet with (IANA name), or None. |
| zone5 | Time zone 5 | Another time zone to meet with (IANA name), or None. |
| on | Date | The date of the meeting in your time zone. Today, unless you change it. |
| start | Working hours start | When the working day starts, on the local clock of every zone. |
| end | Working hours end | When the working day ends, on the local clock of every zone; later than the start. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| overlap | Overlap | How long the working hours of every chosen zone overlap on the date. |
| local1 | Your time zone | The overlap on your clock. |
| local2 | Time zone 2 | The overlap on the clock of time zone 2. |
| local3 | Time zone 3 | The overlap on the clock of time zone 3. |
| local4 | Time zone 4 | The overlap on the clock of time zone 4. |
| local5 | Time zone 5 | The overlap on the clock of time zone 5. |
| none | No overlap | Shown when no time is within the working hours in every zone. |

## Method

For the date in your time zone, take your working hours as a span of moments (UTC); for every other zone, take its working hours on each of its local dates around that date; the overlap is the part of your span inside a span of every other zone, shown on each zone’s clock from the browser’s IANA time zone data.

## Assumptions

- Every zone uses the same working hours, from the start time to the end time on its own clock; the end must be later in the day than the start (no overnight shifts).
- The date is a date in your time zone (the first zone). Your working hours that day are compared with every other zone’s working hours on any of its own dates, so another zone’s part of the overlap can fall on the day before or after, which its date shows.
- A zone’s working hours on a date run from the first moment its clocks show the start time that day to the first moment after that when they show the end time. When the clocks skip a time (spring forward), the moment they jump stands in for it; when they repeat an hour (fall back), the working hours include the repeat.
- Weekends and holidays are not left out: check the weekday shown for each zone.
- Each zone shows the overlap on its own clock as “Mon, Oct 19, 9:00 AM to 11:00 AM”, with the end date too when the overlap crosses midnight on that clock, and several overlaps joined by “; ”. The overlap length is in hours and minutes (“2 hours 30 minutes”, “0 minutes” when there is none).
- Offsets and daylight saving come from the browser’s IANA time zone data (tzdata 2026a when this page was checked). Dates from 2000 to 2040 work.

## Worked examples

1. zone1 = America/New_York, zone2 = Europe/London, zone3 = Europe/Berlin, zone4 = none, zone5 = none, on = 2026-10-19, start = 09:00, end = 17:00 gives overlap = 2 hours, local1 = New York (US Eastern): Mon, Oct 19, 9:00 AM to 11:00 AM, local2 = London, UK: Mon, Oct 19, 2:00 PM to 4:00 PM, local3 = Berlin, Germany: Mon, Oct 19, 3:00 PM to 5:00 PM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
2. zone1 = America/New_York, zone2 = Asia/Kolkata, zone3 = none, zone4 = none, zone5 = none, on = 2026-10-19, start = 09:00, end = 17:00 gives overlap = 0 minutes, none = No time on Monday, October 19, 2026 is between 9:00 AM and 5:00 PM in every zone. Try longer working hours or fewer zones.. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
3. zone1 = America/New_York, zone2 = Asia/Kolkata, zone3 = none, zone4 = none, zone5 = none, on = 2026-10-19, start = 08:00, end = 20:00 gives overlap = 2 hours 30 minutes, local1 = New York (US Eastern): Mon, Oct 19, 8:00 AM to 10:30 AM, local2 = India (New Delhi, Mumbai, Kolkata): Mon, Oct 19, 5:30 PM to 8:00 PM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
4. zone1 = America/Chicago, zone2 = America/New_York, zone3 = Europe/London, zone4 = Europe/Paris, zone5 = Africa/Lagos, on = 2026-10-19, start = 09:00, end = 17:00 gives overlap = 1 hour, local1 = Chicago (US Central): Mon, Oct 19, 9:00 AM to 10:00 AM, local2 = New York (US Eastern): Mon, Oct 19, 10:00 AM to 11:00 AM, local3 = London, UK: Mon, Oct 19, 3:00 PM to 4:00 PM, local4 = Paris, France: Mon, Oct 19, 4:00 PM to 5:00 PM, local5 = Lagos, Nigeria: Mon, Oct 19, 3:00 PM to 4:00 PM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
5. zone1 = America/Los_Angeles, zone2 = Australia/Sydney, zone3 = none, zone4 = none, zone5 = none, on = 2026-10-19, start = 09:00, end = 17:00 gives overlap = 2 hours, local1 = Los Angeles (US Pacific): Mon, Oct 19, 3:00 PM to 5:00 PM, local2 = Sydney, Australia: Tue, Oct 20, 9:00 AM to 11:00 AM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
6. zone1 = America/New_York, zone2 = America/Toronto, zone3 = none, zone4 = none, zone5 = none, on = 2026-03-08, start = 02:30, end = 04:00 gives overlap = 1 hour, local1 = New York (US Eastern): Sun, Mar 8, 3:00 AM to 4:00 AM, local2 = Toronto, Canada: Sun, Mar 8, 3:00 AM to 4:00 AM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
7. zone1 = America/New_York, zone2 = America/Toronto, zone3 = none, zone4 = none, zone5 = none, on = 2026-11-01, start = 01:00, end = 02:00 gives overlap = 2 hours, local1 = New York (US Eastern): Sun, Nov 1, 1:00 AM to 2:00 AM, local2 = Toronto, Canada: Sun, Nov 1, 1:00 AM to 2:00 AM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).
8. zone1 = Pacific/Auckland, zone2 = America/Los_Angeles, zone3 = none, zone4 = none, zone5 = none, on = 2026-10-20, start = 00:00, end = 23:30 gives overlap = 23 hours, local1 = Auckland, New Zealand: Tue, Oct 20, 12:00 AM to 7:30 PM; Tue, Oct 20, 8:00 PM to 11:30 PM, local2 = Los Angeles (US Pacific): Mon, Oct 19, 4:00 AM to 11:30 PM; Tue, Oct 20, 12:00 AM to 3:30 AM. Source: IANA Time Zone Database, tzdata 2026a (https://www.iana.org/time-zones).

## FAQ

### How do I find a meeting time across time zones?

Pick your own time zone first, then the others, the date of the meeting and the working hours. The page shows how long everyone’s working hours overlap and the overlap on each clock. On October 19, 2026, 9:00 AM to 5:00 PM in New York, London and Berlin overlap for 2 hours: 9:00 to 11:00 AM in New York, 2:00 to 4:00 PM in London and 3:00 to 5:00 PM in Berlin.

### What if there is no overlap?

The overlap is 0 minutes, and the page says so. Try longer working hours or fewer zones. New York and India have no overlap from 9:00 AM to 5:00 PM, but with working hours from 8:00 AM to 8:00 PM they overlap for 2 hours 30 minutes: 8:00 to 10:30 AM in New York, 5:30 to 8:00 PM in India.

### Why can the overlap fall on another day?

The date is a date in your time zone, and a zone far east or west of you may already be on the next day or still on the day before. From Los Angeles on Monday, October 19, 2026, the overlap with Sydney is 3:00 to 5:00 PM Monday in Los Angeles and 9:00 to 11:00 AM Tuesday in Sydney. Check the weekday shown for each zone: weekends are not left out.

### Does the planner handle daylight saving time?

Yes. Each zone’s offset on the date comes from your browser’s time zone data, so the overlap moves when one country changes its clocks before another. On a day when the clocks spring forward, a start time that does not exist starts the working hours at the moment of the jump; when they fall back, the repeated hour counts twice.

### Why do New York and India rarely overlap in office hours?

India is 9 hours 30 minutes ahead of New York while New York is on daylight saving time, and 10 hours 30 minutes ahead in winter. So 9:00 AM to 5:00 PM in New York is 6:30 PM to 2:30 AM in India in summer: after the Indian working day.

### Can each zone have its own working hours?

No. Every zone uses the same hours on its own clock, which is the usual way to look for a meeting slot. To allow one office an early start, widen the hours and read that office’s times.

## Sources

- IANA Time Zone Database, tzdata 2026a: the zones and their daylight saving rules. https://www.iana.org/time-zones
- 15 U.S.C. 260a, advancement of time: US daylight saving time from the second Sunday in March to the first Sunday in November. https://www.law.cornell.edu/uscode/text/15/260a